Allison Macfarlane, a geologist and the recently arrived head of the Nuclear Regulatory Commission, chats with the Loop about swapping “professor” for “chairman” — as well as her fondness for “Downton Abbey” and her aversion to heights and lentils.

Which Cabinet secretary would you most like to hang out with, and what would you do?

Ran four geological expeditions to the Himalayas, trekking for hundreds of miles and camping out at high altitude. It really soured me on lentils and rice, which I ate every day for weeks at a time.

What motivated you to go into public service?

White House science adviser John Holdrentaught me that scientists have an obligation to put their knowledge to use in the service of the American people. There’s a place for pure research, but I’ve been most drawn to science that makes a difference in people’s lives.

Favorite TV show?

“Downton Abbey.” It’s like a combination of good chocolate and champagne, absolutely delicious. And since my husband grew up in Britain, it feeds my fascination for the . . . British class system.

What subject, other than your work, do you know most about?

Food and food production. I love cooking for my husband and kids — I think of it as applied chemistry — and I’ve become more and more interested in understanding what’s in what I eat. Reading Michael Pollan’s work completely changed the way I think about food.

What’s the best job you’ve ever had?

The worst was house cleaner. Apart from my current job, which I love, my favorite job was being a research fellow at Stanford University for a year: nothing to do but read and write, cycle and hike in near-perfect weather surrounded by really smart people.

I’m scared of . . .

Heights. My family drove up Mont Ventoux in France last month, and I had my eyes shut whenever there weren’t any guard rails.

What’s one word you wish people would use to describe you?

Real.

You can draft one person in the private sector . . .

Chuck Vest, the former president of MIT. He’s the smartest, most effective administrator I’ve ever known. You could put him in charge of any agency, and he’d improve it. Maybe NRC could find a really hard problem for him to solve.

The skinny on going abroad

Those Republicans skinny-dipping and carousing while traveling in Israel might be causing a collective pearl-clutch, but they’re hardly the first Washington exports to behave badly abroad.

Plenty of others — including those on taxpayer-funded trips and assorted missions — have helped cement long-standing stereotypes of the “Ugly American.” To wit:

●This year, a rowdy group of Secret Service agents traveling to Colombia ahead of President Obamahired hookers after a night of drinking and visits to a strip club. The band of misbehaving fellows (though not law-breaking, as prostitution is legal there) was busted only after one of the gentlemen (ahem) argued over payment.

●While on a 2004 trip to Kazakhstan, then-Rep. Denny Rehberg (R-Mont.) reportedly drank shots of vodka, then fell off a horse, breaking at least one rib. He also reportedly referred to the natives as “coneheads.”

●On a diplomatic trip to South Korea, then-Sen. Bob Toricelli brought along an unusual companion: one of his biggest donors. “The Torch” reportedly invited New Jersey businessman David Chang to a 1999 meeting with the South Korean finance minister in an attempt to help Chang buy an insurance company from that nation’s government.

●Then-Majority Leader Tom DeLay (D-Tex.) was busted for puffing on a Cuban cigar while on a jaunt to Jerusalem in 2003. DeLay had previously railed against communist Cuban smokes, but what happens in Jerusalem . . .